Conduit Bodies: Types, Benefits, and Applications

Updated: October 13, 2025

~10 min read • ~2100 words • Flesch ~60

TL;DR: Pick the right pattern (LB/LL/LR/C/T/X or mogul), verify listing and any cubic-inch marking before splicing, apply 314.28 for 4 AWG and larger pulls, use wet-rated covers and gaskets where required, and document your math. Coastal Long Island jobs favor corrosion-resistant bodies, stainless hardware, and PVC options. When enclosure dimensions or volume come up short, step up to a mogul body or a junction box and clear it with the AHJ.

Why it matters

Conduit bodies make difficult conduit runs practical. They give you access to pull, splice, and inspect conductors without kinking raceway or chewing up labor. On Long Island, jobs see salt air, wind, and fast schedule pressure. The right body type, size, and cover rating saves callbacks and keeps inspectors happy. If you plan to splice in a body, or you are making angle pulls with big raceways, code rules apply. We will hit the highlights with references to the 2023 NEC and note when to call the local AHJ.

Need gear now? Browse our conduit bodies and fittings to stock the job before rough-in.

Fundamentals

What a conduit body is. A conduit body is a fitting with a removable cover that provides access to the interior of a raceway system. Common patterns include LB, LL, LR, C, T, and X. Mogul styles are deeper for larger conductors and bending radii.

Common patterns.

• LB: Conduit in on the back, out on the end. Go-to for a 90-degree change with the cover facing you.
• LL/LR: Similar to LB but end opening points left or right to suit the run.
• C: Straight-through pull point with openings on both ends.
• T: Three openings to branch in one plane.
• X: Four-way cross when systems intersect.
• Mogul: Oversized interior for larger conductors or tighter geometries.

Materials and ratings. Aluminum and zinc bodies are light and durable. Gray PVC is common for corrosive or buried work. Stainless covers and hardware help at coastal sites. Look for environmental ratings such as NEMA 3R, 4, or 4X when you need weather or corrosion protection. For wet locations, use the manufacturer’s gasketed cover and torque the screws evenly. See PVC conduit bodies for corrosive sites if you work near marinas or south shore exposure.

Listings and markings. Conduit bodies are typically listed under UL 514B. Use them only as they are listed and marked. Some bodies are marked with a volume in cubic inches; those can be used for splices if installed per the marking and code. If there is no marked volume, treat it as a pull point only.

Code & compliance (NEC 2023 refs)

Use listed equipment as marked. NEC 110.3(B) requires installing and using equipment per listing and labeling. If your body is not marked for splices, do not splice in it. Good workmanship is covered in 110.12, and terminations are in 110.14.

Wet location rules. Interiors of raceways in contact with earth or in outdoor locations are often considered wet. Follow 300.9 and select conductors rated for wet locations. Use covers and gaskets suitable for the environment. Where underground, see 300.5 for cover depth and routing coordination.

Box fill and splices in conduit bodies. Article 314 governs box fill. Section 314.16 covers volume requirements, and 314.16(C)(2) addresses splices in conduit bodies if the body is marked with a volume. Use the marked volume and the conductor allowances from the code to size correctly. If there is no volume marking, do not splice. When equipment grounding conductors are present, include them in the fill per 250.148 and 314.16(B).

Pull-point sizing for large conductors. Section 314.28 applies when any conductor is 4 AWG or larger. Straight pulls require a minimum length equal to 8 times the trade size of the largest raceway. Angle pulls use the 6-times rule plus additions depending on raceway arrangement. We show math in the examples below.

Raceway compatibility. Match the body and hubs to the raceway Article: IMC 342, RMC 344, PVC 352, EMT 358, LFMC 350, LFNC 356. Bonding of metal raceways and fittings is in 250.96.

Local adoption note. Long Island jurisdictions can amend or adopt the NEC on different cycles. Always confirm with the local AHJ before finalizing layout, splices, or pull-box calculations.

For help picking covers and gaskets that pass inspection, see our wet-location boxes and covers.

Selection steps

Step 1: Choose the body pattern

Start with the geometry. Use LB/LL/LR to turn a corner with access. Use C as a straight pull point on long runs. Use T or X when you must branch or cross. If conductors are large or you need more depth for bending radius, spec a mogul body.

Step 2: Match material and enclosure rating

Indoors and dry: die-cast or aluminum is fine. Outdoors or washdown: pick NEMA 4 or 4X with stainless hardware. Coastal jobs often deserve PVC or 4X to resist corrosion. Confirm gasket type and replacement availability. We stock gaskets and replacement covers that fit common brands.

Step 3: Size by raceway and conductor

Match hub size to raceway trade size. If any conductor is 4 AWG or larger, verify the interior dimensions meet 314.28. For splicing in the body, verify that the body is marked with a volume and that the volume covers all conductors per 314.16. When in doubt, upsize to a mogul body or plan the splice in a junction box.

Step 4: Verify box-fill volume if splicing

Find the cubic-inch marking inside the body or on the datasheet. Calculate conductor fill using the allowances from NEC 314.16(B). Each unbroken conductor that passes through without splice usually counts once, each pigtail counts once, and internal clamps count as conductors as specified by code. Compare your total allowance to the marked volume. If you come up short, pick the next size up or move the splice to a box.

Step 5: Covers, gaskets, and hardware

Use the manufacturer’s cover and gasket for the exact body pattern. Replace dried or cracked gaskets. Use anti-seize on stainless screws near the coast. Where frequent access is expected, consider a hinged cover rated for the environment.

Step 6: Listing, marking, and AHJ check

Confirm the UL listing, pattern, hub size, and any cubic-inch marking. Document your box-fill and pull calculations. If your run is complex or space-constrained, send a quick sketch to the AHJ for concurrence before you cut in the bodies. It saves rework. For connectors that match your raceway, see EMT connectors and couplings.

Sizing & configuration examples (with math)

Example A: Splice in an LB with #12 THHN

Scenario: You need to splice three 2-wire cables plus ground in a listed LB marked 18 in³. Conductors are #12 THHN.

• Conductor allowance for #12 from NEC Table 314.16(B) is 2.25 in³ per conductor.
• Count: Two ungrounded and one neutral per cable = 3 conductors per cable. Three cables = 9 conductors.
• Equipment grounding conductors together count as one conductor = 1.
• Total count = 10 conductors.
• Volume needed = 10 × 2.25 in³ = 22.5 in³.

Result: The 18 in³ LB is undersized. Upsize to a body marked at least 22.5 in³. Cite 314.16 and 314.16(C)(2) because this is a splice in a conduit body.

Example B: Straight pull with 2 in. EMT

Scenario: You plan a straight-through pull using a C-body on 2 in. EMT with 3 conductors of 3/0 THHN. Section 314.28(A)(1) requires the minimum length to be 8 times the trade size of the largest raceway for straight pulls.

• Largest raceway trade size = 2 in.
• Minimum length = 8 × 2 in. = 16 in.

Result: The interior length from entry to exit must be at least 16 inches. Most standard C-bodies are smaller, so a mogul body or a junction box is required.

Example C: Angle pull with 1.5 in. PVC, one raceway per wall

Scenario: An LL body turns a corner with one 1.5 in. raceway into each end. Section 314.28(A)(2) requires the distance from the raceway entry to the opposite wall to be at least 6 times the trade size of the largest raceway for angle pulls, when there is one raceway on each of two walls.

• Largest raceway trade size = 1.5 in.
• Minimum distance from each entry to opposite wall = 6 × 1.5 in. = 9 in.

Result: The internal dimensions must give at least 9 inches from each entry to the opposite wall. Many compact LL bodies will not meet this. Use a larger mogul body or a junction box to maintain compliance.

Stock pulling aids to cut friction and labor on long runs. See our wire pulling lubricants for EMT and PVC work.

Installation & wiring notes

• Orientation and slope. Install with the cover accessible and, outdoors, slope entries so water drains away from terminations. Treat raceway interiors as wet where 300.9 applies and use conductors rated for wet locations.
• Thread engagement. For threaded hubs, seat snugly without over-torquing. Use listed thread seal if the manufacturer specifies. For PVC hubs, solvent weld per the cement instructions and allow cure time before pulling.
• Bonding and grounding. Bond metal raceways and fittings per 250.96. If you splice equipment grounds inside a marked body, include them in fill per 314.16(B).
• Covers and gaskets. Use the exact cover and gasket for that body. Replace brittle gaskets. On coastal jobs, stainless screws with anti-seize resist galling. See gaskets and replacement covers.
• Conductor handling. Use pull lube compatible with insulation. Avoid tight figure-eight piles inside the body. Respect bending radii. Stage wire pulling lubricants on long pulls.
• Marking and access. Keep labels readable. Do not paint over volume or environmental markings. NEC 110.3(B) expects compliance with markings.

Testing, commissioning, documentation

• Continuity and insulation tests. Verify equipment ground continuity. Where specified, perform insulation resistance tests before energizing and record values by segment.
• Torque and reaccess. Torque terminations per 110.14. Retighten cover screws after one thermal cycle outdoors. File any datasheet that states cubic inches or interior dimensions with the closeout set.
• Photos and sketches. Photograph interiors before closing, especially when relying on a volume mark for splices or 314.28 for clearances. Store sketches and math with the job packet.

Troubleshooting

• Water in the body. Check gasket, cover torque, and conduit pitch. If condensation is chronic, add drains where listed or relocate. Confirm conductors are wet-rated per 300.9.
• Hard pulls or insulation scuffing. Upsize to a mogul body, add an intermediate pull point, or reroute to reduce angle severity. Verify 314.28 clearances for 4 AWG and larger.
• Trips after rework. Inspect splices if the body is marked for them. Recheck box-fill under 314.16(B) and 314.16(C)(2). Look for nicks at the hub lip.
• Corrosion. Swap to PVC or 4X-rated bodies with stainless hardware. Use anti-seize and schedule gasket replacement.

Common mistakes

• Splicing in a body with no marked volume. 110.3(B) and 314.16(C)(2) do not allow it.
• Ignoring 314.28 when any conductor is 4 AWG or larger.
• Using dry-location wire in raceways treated as wet by 300.9.
• Miscounting box fill. Include grounds, pigtails, and internal clamps when applicable.
• Mixing materials without proper transition fittings. Match the raceway Article to the body and hubs.

Parts to stock

• LB, LL, LR, C, T, and X bodies in common trade sizes, plus mogul versions for larger feeders.
• Assorted covers and gaskets, including hinged options for frequent access.
• Stainless cover screws, anti-seize, and corrosion inhibitors for coastal installs. See stainless hardware and anti-seize.
• EMT, PVC, and RMC compatible connectors and couplings. See EMT connectors and couplings.
• Pull tape, swivels, and wire pulling lubricants.

When to call the AHJ or an engineer

• Any time you plan splices in a conduit body and volume is tight or the marking is unclear.
• When 314.28 clearance looks marginal and field dimensions do not match catalog drawings.
• Where environmental ratings are disputed, such as splash zones, washdown, or direct spray.
• When local amendments differ from the base 2023 NEC. Long Island jurisdictions may vary.

Safety disclaimer

This guide is for licensed professionals. Follow the 2023 NEC, manufacturer instructions, and local amendments. Use listed and labeled equipment only as marked. De-energize circuits, verify absence of voltage, and wear appropriate PPE.

FAQ

Can I splice in any conduit body?
No. Only in bodies marked with a volume and within that limit per 314.16(C)(2). If there is no marked volume, treat it as a pull point.

Do I need wet-rated conductors inside outdoor raceways?
Yes where 300.9 applies. Treat the interior as a wet location and use conductors rated accordingly.

What if my 2 in. feeder will not fit a standard C-body?
Apply 314.28. If the internal length is less than 8 times the raceway trade size for straight pulls, move up to a mogul body or a junction box.

Are PVC bodies acceptable at the shore?
Often yes for corrosion resistance. Use the correct gasketed cover and confirm ratings such as 4 or 4X with the AHJ.

How do I count grounds for box fill?
Equipment grounding conductors together count as one conductor of the largest size present when applying 314.16(B).

Which Articles cover different raceways?
IMC 342, RMC 344, PVC 352, EMT 358, LFMC 350, LFNC 356. Bonding is in 250.96.

Author: Revco Editorial Team — Electrical Content Editor
Technical review: Pending — add approved name/credential
Contact: (631) 283-3600

About Revco Lighting & Electrical Supply

Since 1978, Revco Lighting & Electrical Supply has been helping professionals bring their projects to light—literally. As a go-to source for lighting and electrical products across Long Island, NY and nearby areas, we specialize in supporting contractors, builders, and industry experts with practical solutions and dependable service. Whether it’s a complex commercial build or a simple residential upgrade, we’re here to make sure you have what you need, when you need it.

Sources

1. NFPA. “NFPA 70: National Electrical Code, 2023 Edition.” nfpa.org/codes-and-standards/.../70. Retrieved 10-2025.
2. NEMA. “FB 1: Fittings.” nema.org/standards/view/fb-1. Retrieved 10-2025.
3. UL Standards. “UL 514B: Conduit, Tubing, and Cable Fittings.” shopulstandards.com/.../UL514B. Retrieved 10-2025.
4. Emerson Appleton. “Conduit Outlet Bodies (LB/LL/LR/C/Mogul).” emerson.com/.../appleton-conduit-outlet-bodies. Retrieved 10-2025.
5. EC&M. “Can You Make Splices in a Conduit Body?” ecmweb.com/.../can-you-make-splices-in-a-conduit-body. Retrieved 10-2025.
6. OSHA. “1910 Subpart S — Electrical.” osha.gov/.../1910SubpartS. Retrieved 10-2025.